EP0811123B1 - Gas actuated slide valve in a screw compressor - Google Patents

Gas actuated slide valve in a screw compressor Download PDF

Info

Publication number
EP0811123B1
EP0811123B1 EP95943005A EP95943005A EP0811123B1 EP 0811123 B1 EP0811123 B1 EP 0811123B1 EP 95943005 A EP95943005 A EP 95943005A EP 95943005 A EP95943005 A EP 95943005A EP 0811123 B1 EP0811123 B1 EP 0811123B1
Authority
EP
European Patent Office
Prior art keywords
compressor
refrigerant gas
pressure
conduit
working fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP95943005A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0811123A1 (en
Inventor
Rodney L. Lakowske
Arthur L. Butterworth
Garry E. Andersen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Trane US Inc
Original Assignee
American Standard Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Standard Inc filed Critical American Standard Inc
Publication of EP0811123A1 publication Critical patent/EP0811123A1/en
Application granted granted Critical
Publication of EP0811123B1 publication Critical patent/EP0811123B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/10—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
    • F04C28/12—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves
    • F04C28/125—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves with sliding valves controlled by the use of fluid other than the working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/40—Pumps with means for venting areas other than the working chamber, e.g. bearings, gear chambers, shaft seals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S418/00—Rotary expansible chamber devices
    • Y10S418/01—Non-working fluid separation

Definitions

  • the present invention relates to the compression of gas in a rotary compressor. More particularly, the present invention relates to the control of the position of a slide valve in a refrigeration screw compressor.
  • Compressors are used in refrigeration systems to raise the pressure of a refrigerant gas from an evaporator to a condenser pressure (more generically referred to as suction and discharge pressures respectively) which permits the ultimate use of the refrigerant to cool a desired medium.
  • compressors including rotary screw compressors, are commonly used in such systems.
  • Rotary screw compressors employ male and female rotors mounted for rotation in a working chamber which is a volume shaped as a pair of parallel intersecting flat-ended cylinders closely toleranced to the exterior dimensions and shapes of the intermeshed screw rotors.
  • a screw compressor has low and high pressure ends which respectively define suction and discharge ports that open into the working chamber.
  • Refrigerant gas at suction pressure enters the suction port from a suction area at the low pressure end of the compressor and is delivered to a chevron shaped compression pocket formed between the intermeshed rotors and the interior wall of the working chamber.
  • the compression pocket is closed off from the suction port and gas compression occurs as the pocket's volume decreases.
  • the compression pocket is circumferentially and axially displaced to the high pressure end of the compressor where it comes into communication with the discharge port.
  • Screw compressors most typically employ slide valve arrangements by which the capacity of the compressor is controlled over a continuous operating range.
  • the valve portion of a slide valve assembly is disposed within and constitutes a part of the rotor housing. Certain surfaces of the valve portion of the slide valve assembly cooperate with the rotor housing to define the working chamber of the compressor.
  • Slide valves are axially moveable to expose a portion of the working chamber and the rotors therein to a location within a screw compressor, other than the suction port, which is at suction pressure. As a slide valve opens to greater and greater degrees, a larger portion of the working chamber and the screw rotors therein are exposed to suction pressure other than through the suction port. The portion of the rotors and working chamber so exposed is prevented from engaging in the compression process and the compressor's capacity is proportionately reduced.
  • the positioning of the slide valve between the extremes of the full load and unload positions is relatively easily controlled as is, therefore, the capacity of the compressor and the system in which it is employed. Historically, slide valves have been positioned hydraulically using oil which has a multiplicity of other uses within the compressor.
  • Such oil is most typically sourced from an oil separator where discharge pressure is used to drive oil from an oil sump in the separator to compressor injection ports and bearing surfaces and to control the position of the slide valve.
  • discharge pressure is used to drive oil from an oil sump in the separator to compressor injection ports and bearing surfaces and to control the position of the slide valve.
  • the pressure differential between the relatively higher pressure source of the oil (the oil separator) and a location within the compressor which is at a relatively lower pressure is taken advantage of to ultimately return the oil, after its use, to the oil separator.
  • oil which has been used for its intended purpose in a screw compressor is vented or drained from the location of its use to a relatively lower pressure location within the compressor or in the system in which the compressor is employed.
  • oil is vented or drained to, or is used in the first instance, in a location which contains refrigerant gas at suction pressure or at some pressure which is intermediate compressor suction and discharge pressure.
  • Such oil mixes with and becomes entrained in the refrigerant gas in the location to which it is vented, drained or used and is delivered back to the oil separator, at discharge pressure, in the stream of compressed refrigerant gas discharged from the compressor.
  • the oil is separated from the refrigerant gas in the separator and is deposited in the sump therein from which it is directed, most often using the discharge pressure which exists in the oil separator, back to the compressor locations identified above for further use. Even after the occurrence of the separation process, however, the oil in the sump of the oil separator will contain refrigerant gas bubbles and/or quantities of dissolved refrigerant.
  • the separated oil may, in fact, contain from 10-20% refrigerant by weight depending upon the solubility properties of the particular oil and refrigerant used.
  • Still another disadvantage in the use of oil to hydraulically position the slide valve in a refrigeration screw compressor relates to the fact that the quantity of refrigerant gas bubbles and dissolved liquid refrigerant contained therein varies with time and with the characteristics and composition of the particular batch of lubricant delivered to the slide valve actuating cylinder.
  • slide valves are most typically controlled through a supposition that the opening of a load or unload solenoid valve for a predetermined period of time results in slide valve movement that is repeatable and consistent with that period of time. That supposition is, in turn, predicated on the supposition that the characteristics and composition of the oil directed to or vented from the slide valve actuating cylinder during such a period of time is consistent.
  • GB-A-2085080 drawn to our attention during the International phase of the present application discloses a refrigeration screw compressor having a suction port and a discharge port and comprising a housing defining a working chamber in flow communication with the suction and discharge ports of the compressor, a male rotor disposed in the working chamber, a female rotor disposed in the working chamber in meshing engagement with the male rotor whereby, in use, rotation of the male and female rotors operate to compress a gaseous working fluid within the working chamber from a suction to a discharge pressure, a slide valve having an actuating piston, and means including a conduit for selectively communicating the actuating piston with the compressor high-pressure side to effect loading of the compressor or with the compressor low-pressure side to effect unloading of the compressor.
  • the present invention provides a refrigeration screw compressor, having a suction port and a discharge port and comprising: a housing defining a working chamber in flow communication with said suction and said discharge ports of said compressor; a male rotor disposed in said working chamber; a female rotor disposed in said working chamber in meshing engagement with said male rotor whereby, in use, rotation of said male and said female rotors operate to compress a gaseous working fluid within said working chamber from a suction to a discharge pressure; a slide valve having an actuating piston; first means including a first conduit adapted to selectively communicate refrigerant gas from any one of a first and second source of refrigerant gas to said actuating piston, such that regardless of which source is selected the source from which said refrigerant gas is communicated is at a pressure sufficient to move said slide valve in a direction which loads said compressor; and second means including a second conduit adapted to selectively vent refrigerant gas communicated to said actuating piston to a location in said compressor where
  • the pressure of at least one of the said first and second sources of refrigerant gas equals or exceeds discharge pressure when said compressor is in operation and wherein said first conduit communicates refrigerant gas from the one of said first and second sources of refrigerant gas which is at a higher pressure.
  • said first source of refrigerant gas is upstream of said discharge port and said second source of refrigerant gas is downstream of said discharge port.
  • the compressor may further comprise valve means, responsive to the respective pressures of said first and said second sources of refrigerant gas, for opening said first conduit to said higher pressure source of refrigerant gas and closing said first conduit off from the other source of refrigerant gas.
  • valve means responsive to the respective pressures of said first and said second sources of refrigerant gas, for opening said first conduit to said higher pressure source of refrigerant gas and closing said first conduit off from the other source of refrigerant gas.
  • the above-mentioned valve means may be automatically operative, in response to the circumstances where the pressure in said other source of refrigerant gas comes to exceed the pressure in said higher pressure source of refrigerant gas, to open said first conduit to said other source of refrigerant gas and to close said first conduit off from said higher pressure source of refrigerant gas.
  • first and second means respectively comprise first and second solenoid valves, said first solenoid valve being disposed in said first conduit such that, in use, when said first solenoid valve is open, the flow of refrigerant gas through said first conduit occurs, said second solenoid valve being disposed in said second conduit such that when said second solenoid valve is open, the venting of refrigerant gas through said second conduit occurs.
  • the first source of refrigeration gas may be a closed compression pocket defined in said working chamber by said male and said female rotors. Further the location to which refrigerant gas communicated to said actuating piston is vented may be a closed compression pocket defined in said working chamber in which the compression of the refrigerant gas contained therein has not yet commenced.
  • the first and second conduits may comprise passages defined internal of said housing.
  • the housing may be comprised of a rotor housing and a bearing housing, said first and said second conduits being passages defined at least partly in said bearing housing.
  • the invention also includes a refrigeration system comprising: an oil separator; a condenser; a metering valve; an evaporator; and a screw compressor for compressing, in operation, a gaseous working fluid from a suction to a discharge pressure in a working chamber which is in flow communication with a suction port and a discharge port, said compressor having a slide valve which is actuatable by gaseous working fluid sourced from any one of at least two locations within said refrigeration system, the refrigeration system having means which always selectively sources the working fluid for actuating the slide valve from the higher pressure location of said at least two locations.
  • Both of the above-mentioned two locations may be internal of said compressor.
  • the other location is said oil separator.
  • the refrigeration system may further comprise first means including a first conduit adapted to selectively communicate between said at least two locations within said refrigeration system and said slide valve, and second means including a second conduit adapted to selectively communicate between said slide valve and a location in said working chamber of said compressor where the pressure of said gaseous working fluid is less than discharge pressure.
  • the refrigeration system may further comprise valve means, automatically responsive to the respective pressures of said first and said second locations from which gaseous working fluid is sourced, for opening said first conduit to the higher pressure one of said first and said second locations and for closing said first conduit off from the other of said first and said second locations.
  • said first and second means respectively comprise first and second solenoid valves, said first solenoid valve being disposed in said first conduit such that, in use, when said first solenoid valve is open, the flow of gaseous working fluid through said first conduit occurs, said second solenoid valve being disposed in said second conduit such that when said second solenoid valve is open, the venting of gaseous working fluid through said second conduit occurs.
  • the invention also includes a method of controlling the position of a slide valve in a refrigeration screw compressor which compresses a gaseous working medium from a suction to a discharge pressure in a working chamber having a suction port and a discharge port, said method comprising the steps of: supplying said gaseous working fluid to said compressor at a suction pressure; compressing said gaseous working fluid in the working chamber of said compressor; discharging said gaseous working fluid from said working chamber of said compressor through said discharge port; controlling the position of the slide valve, so as to load said compressor by the use of gaseous working fluid selectively sourced from any one of two locations, one of said locations being downstream of said discharge port and the other of said two locations being upstream of said discharge port and in said working chamber.
  • said controlling step includes the step of automatically selecting to source said gaseous working fluid from the higher pressure one of said two locations without signal or control from exterior of said system.
  • said step of selecting to source said gaseous working fluid from the higher pressure one of said two locations may include the step of selecting to source said gaseous working fluid from a location downstream of said discharge port and external of said compressor.
  • the method may also comprise the further step of venting said gaseous working fluid used to load said compressor to a closed compression pocket in said working chamber which is at a pressure less than discharge pressure in order to unload said compressor.
  • refrigeration system 10 is comprised of a compressor assembly 12, an oil separator 14, a condenser 16, an expansion device 18 and an evaporator 20 all of which are serially connected for the flow of refrigerant therethrough.
  • Compressor assembly 12 includes a rotor housing 22 and a bearing housing 24 which together are referred to as the compressor housing.
  • a male rotor 26 and a female rotor 28 are disposed within working chamber 30 of the compressor which is cooperatively defined by rotor housing 22, bearing housing 24 and the valve portion 32 of slide valve assembly 34.
  • Slide valve assembly 34 which in the preferred embodiment is a so-called capacity control slide valve assembly, is additionally comprised of connecting rod 36 and actuating piston 38.
  • One of male rotor 26 or female rotor 28 is driven by a prime mover such as electric motor 40.
  • Refrigerant gas at suction pressure is directed from evaporator 20 to communicating suction areas 42 and 42A at the low pressure end of compressor 12.
  • Gas at suction pressure flows into suction port 44, in this case underneath the rotors, and enters a compression pocket defined between rotors 26 and 28 and the interior surface of working chamber 30.
  • the compression pocket is reduced in size and is circumferentially displaced to the high pressure end of the compressor where the now compressed gas flows out of the working chamber through discharge port 46 and into discharge passage 48.
  • discharge port 46 is comprised of two portions.
  • the first portion being radial portion 46A which is formed on the discharge end of valve portion 32 of the slide valve assembly and the second portion being axial portion 46B which is formed in the discharge face of the bearing housing.
  • the geometry and interaction of these two discharge port portions with the slide portion of the slide valve assembly controls compressor capacity and efficiency.
  • Both portions of discharge port 46 affect compressor capacity until the slide valve assembly 34 unloads far enough such that the radial discharge port is no longer located over the screw rotors. In that condition it is only the axial port which is active, with the slide, in determining compressor capacity. Therefore, during compressor startup, when slide valve assembly 34 is in the full unload position, the axial portion of discharge port 46 will be the only active portion of the discharge port.
  • Discharge gas which has oil entrained in it, is directed out of the discharge port and discharge passage to oil separator 14 where the oil is separated from the compressed refrigerant gas and settles into sump 50.
  • the discharge pressure in the gas portion 52 of oil separator 14 acts on the oil in sump 50 to drive such oil through supply lines 54, 56 and 58 to various locations within compressor 12.
  • oil supply line 54 provides oil to lubricate bearing 60 while supply line 56 directs oil to injection passage 62 in the rotor housing.
  • Supply line 58 directs oil to bearing 64 at the high pressure end of the compressor.
  • Slide valve actuating piston 38 is disposed in actuating cylinder 66 within bearing housing 24.
  • the position of the slide valve actuating piston within cylinder 66 is determinative of the position of valve portion 32 of the slide valve assembly within rotor housing 22. Because of the relative surface areas of the faces of valve portion 32 and piston 38 which are exposed to discharge pressure in passage 48 and because the end face of valve portion 32 which abuts slide stop 68 of the compressor is exposed to suction pressure while the face of piston 38 facing into cylinder 66 is selectively acted upon by fluid at discharge pressure or higher, the admission of gaseous fluid to cylinder 66 through aperture 69 will cause slide valve movement in the direction of arrow 70 to load the compressor.
  • slide valve assembly 34 is illustrated in the full load position with valve portion 32 in abutment with slide stop 68. In that position, working chamber 30 and the male and female screw rotors are exposed to the suction area of the compressor through suction port 44.
  • the slide valve will be positioned to the full unload position when the compressor shuts down so that the current drawn by the compressor motor at startup remains within limits.
  • a signal is sent by controller 72 to position load solenoid valve 74 to permit flow therethrough.
  • load solenoid valve 74 In the open position, pneumatic fluid in the form of refrigerant gas is permitted to flow through the load solenoid and into actuating cylinder 66 so as to permit such fluid to act on slide valve actuating piston 38 and cause its movement in the direction of arrow 70.
  • the source of gas in the overcompression circumstance is a closed compression pocket internal of working chamber 30 of compressor 12.
  • Such chamber is placed in flow communication with load solenoid valve 74 through shuttle check valve assembly 76 which is disposed in bore 78 in bearing housing 24.
  • Bore 78 is, however, also capable of being placed in flow communication with discharge passage 48 through passage 80 as will subsequently be described.
  • Passage 84 communicates between bore 78 and load solenoid valve 74.
  • Passage 82 communicates through opening 30A between a closed compression pocket in working chamber 30 and bore 78. Opening 30A is located so as to communicate gas out of the closed compression pocket, on either the male or female rotor side, just prior to the opening of that pocket to the discharge port when the average pocket pressure is at its highest.
  • Shuttle check valve assembly 76 is of a commercially available type and is retained in place within bore 78 by positioning spring 86 and closure nut 88. Washers 90 and 92 act as seating surfaces for spring 86 and valve 76 respectively while O-rings 94 and 96 provide a fluid tight seal between valve assembly 76 and the inner surface of bore 78.
  • Valve assembly 76 itself defines an axially running passage 98 in which ball 100 is rollably disposed. Passage 98 is in flow communication with passage 84 through ports 98A which communicate with peripheral groove 98B defined by valve assembly 76.
  • port 30A can open into either the male or female rotor side of the working chamber and that it is positioned so as to be in communication with a compression pocket immediately prior to the opening of that compression pocket to the discharge port. It is also to be noted that port 30A could open radially into such pocket through the use of radial passages (not shown) drilled into the rotor housing and/or slide portion of the slide valve. It is further to be noted that rather than communicate with discharge passage 48, passage 80 could run from bore 78 directly to oil separator 14 or to the conduit connecting discharge passage 48 of the compressor assembly to the oil separator with the same results being achieved.
  • passage 80 is closed off from passage 84 and passage 84 is opened to the flow of gas from working chamber 30.
  • gas is directed from load solenoid valve 74 into actuating cylinder 66 so as to further load the compressor by moving actuating piston 38 and the slide valve assembly in the direction of arrow 70.
  • controller 72 closes load solenoid valve 74 thereby isolating cylinder 66 from passage 84 and from both of its sources of pneumatic actuating fluid.
  • the gas trapped in cylinder 66 by the closure of load solenoid valve 74 maintains the position of piston 38 and slide valve assembly 34 constant until load solenoid valve 74 is next opened or until unload solenoid valve 102 is opened as will further be described.
  • discharge passage 48 acts on ball 100 to position it against the relatively lower pressure in passage 82 so as to close off passage 82 from communication with passage 84.
  • Discharge passage 48 is thereby placed in flow communication with passage 84 and, upon the opening of the load solenoid, with slide valve actuation cylinder 66 to provide the impetus by which actuating piston 38 of slide valve assembly 34 is caused to further load the compressor.
  • valve assembly 76 the position of ball 100 within valve assembly 76 and the source of gaseous actuating fluid by which compressor 12 is further loaded is predicated on which of the sources of such gas, discharge passage 48 or working chamber 30, is at the higher pressure. That source will automatically be the source of pneumatic slide valve actuating fluid which is immediately available upon the opening of the load solenoid valve.
  • load solenoid valve 74 is closed and unload solenoid valve 102 is opened by controller 72.
  • the positioning of unload solenoid valve 102 in the open position places cylinder 66 in flow communication through passage 104 with a location within compressor 12, such as bearing cavity 106, which is preferably at or near suction pressure.
  • unload solenoid valve 102 therefore vents cylinder 66 and the relatively much higher pressure fluid contained within it to a relatively much lower pressure location within the compressor assembly causing slide valve assembly 34 to move in the direction of arrow 108.
  • the surface areas of the slide valve assembly are designed such that the net effect of the gas forces acting on them, under the circumstance where cylinder 66 is vented, is to urge the slide valve assembly in the direction of arrow 108.
  • the closure of unload solenoid valve 102 stops the movement of slide valve assembly 34 in that direction and maintains the position of the slide valve and the load on the compressor constant until the next opening of either the load or unload solenoid valves.
  • Bearing cavity 106 preferably drains or vents, such as through passage 110 and opening 30B, to a so-called "idling" pocket within the working chamber of the compressor which is at or near suction pressure.
  • a pocket is a closed pocket, that is, a pocket closed off from suction, in which the compression process has not yet begun to occur.
  • shuttle check valve assembly 76 is replaced by individual check valves 176A and 176B which are each in flow communication with load solenoid valve 74 through conduit 84.
  • Conduit 82 connects to check valve 176B.
  • check valve 176A is in flow communication through line 178 with discharge gas portion 52 of oil separator 14. It will be appreciated that like valve assembly 76, individual check valves 176A and 176B could be housed within bearing housing 24 or, as schematically illustrated, can be disposed in piping external of the compressor.
  • the embodiment of Figure 6 is also somewhat different in that bearing cavity 106, rather than venting axially into an idler pocket in the working chamber 30 through opening 30B the end face of the bearing housing, as described with respect to Figures 1-5, is vented through passage 180 in the bearing housing which aligns and communicates with passage 182 of the rotor housing. Passage 182, like opening 30B in the Figures 1-5 embodiment, opens into an idler pocket within working chamber 30.
  • the embodiment of Figure 6 otherwise functions in the same manner as the embodiment of Figures 1-5 in every respect.
  • Hot start conditions occur when the temperature differential between the system condenser and the system evaporator at compressor startup is such that it is difficult to build sufficient pressure in the oil separator to ensure an adequately pressurized supply of oil to the compressor in a timely manner.
  • a successful "hot start” is considered to be achieved when a predetermined differential suction to discharge pressure is achieved which is sufficient to drive oil to the compressor prior to the time a differential pressure safety control would otherwise shut down the compressor.
  • a compressor embodying the present invention has been successful in achieving "hot starts” in a laboratory setting where the condenser temperature was 32°F below the evaporator temperature at startup.
  • prior hydraulically actuated slide valve actuation schemes often required that condenser temperatures be at least 10°F above evaporator temperature to assure a successful start, that is, a start in which pressure develops quickly enough in the oil separator to assure an adequately pressurized supply of oil to the compressor in a timely manner.
  • the pressure which develops in a compression pocket in the compressor's working chamber immediately prior to its opening to the discharge port is higher than the pressure downstream thereof.
  • the compressor is "overcompressing" the refrigerant gas under such conditions to a pressure which decreases as soon as the compression pocket opens to the discharge port.
  • such overcompression is taken advantage of, under hot start conditions, to immediately provide an actuating fluid of sufficient pressure by which to effect the movement of the slide valve to load the compressor.
  • gas from downstream of the compressor discharge port will automatically take over the function of actuating the slide valve to the extent that overcompression ceases to occur within the compressor.
  • an additional advantage of the gas actuation arrangement is that its implementation can be accomplished through the use of flow passages formed only in the bearing housing and passages which do not need to be aligned with or communicate with passages in the rotor housing of the compressor.
  • the present invention is equally applicable to the control of slide valves and screw compressors of types other than capacity control slide valves.
  • the slide valve actuation arrangement of the present invention is applicable to the control of so-called volume ratio control slide valves as well as to the control of multiple slide valves in a screw compressor whatever their purpose, number or type might be.
  • compressors embodying the present invention are more predictably and accurately controlled due to the consistency of refrigerant gas, when employed as an actuating fluid, as compared to the relatively inconsistent makeup, in terms of entrained gas bubbles and/or dissolved refrigerant, of the hydraulic fluid most typically used in such applications.
  • consistency of the gaseous medium used to control the position of the slide valve assembly much more precise and repeatable control of slide valve position is achieved and compressor efficiency is enhanced.
  • the illustrated embodiments comprise a screw compressor having a slide valve the position of which is controlled through the use of a gaseous medium.
  • the medium is a fluid comprised of the gas which undergoes compression within the compressor and is sourced from either the system in which the compressor and the gas is employed or from a location in the working chamber of the compressor.
  • the compressor slide valve is connected by a rod to a piston slideably disposed in an actuating cylinder.
  • Load and unload solenoid valves operate and are controlled to admit gaseous fluid to or vent fluid from the cylinder so as to position the slide valve such that the compressor produces compressed refrigerant gas at a rate in accordance with the demand on the system in which the compressor is employed.
  • the load solenoid valve is in flow communication with two different sources of refrigerant gas through a common conduit. By opening the load solenoid valve, gas is admitted to the cylinder in which the slide valve actuating piston is disposed causing, in turn, the slide valve to move in a direction which further loads the compressor.
  • a check valve arrangement is disposed between the two or more sources of gas and the load solenoid valve so that the gas supplied to the load solenoid valve to activate the slide piston is automatically sourced from the one of the two or more sources where pressure is highest.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
EP95943005A 1995-02-24 1995-12-06 Gas actuated slide valve in a screw compressor Expired - Lifetime EP0811123B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US393957 1982-06-30
US08/393,957 US5509273A (en) 1995-02-24 1995-02-24 Gas actuated slide valve in a screw compressor
PCT/US1995/015827 WO1996026368A1 (en) 1995-02-24 1995-12-06 Gas actuated slide valve in a screw compressor

Publications (2)

Publication Number Publication Date
EP0811123A1 EP0811123A1 (en) 1997-12-10
EP0811123B1 true EP0811123B1 (en) 2000-03-22

Family

ID=23556941

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95943005A Expired - Lifetime EP0811123B1 (en) 1995-02-24 1995-12-06 Gas actuated slide valve in a screw compressor

Country Status (11)

Country Link
US (1) US5509273A (zh)
EP (1) EP0811123B1 (zh)
JP (1) JPH11500511A (zh)
KR (1) KR100350839B1 (zh)
CN (1) CN1080391C (zh)
AU (1) AU4416696A (zh)
BR (1) BR9510274A (zh)
CA (1) CA2212942C (zh)
DE (1) DE69515911T2 (zh)
IN (1) IN185020B (zh)
WO (1) WO1996026368A1 (zh)

Families Citing this family (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5832737A (en) * 1996-12-11 1998-11-10 American Standard Inc. Gas actuated slide valve in a screw compressor
US5979168A (en) * 1997-07-15 1999-11-09 American Standard Inc. Single-source gas actuation for screw compressor slide valve assembly
US5950443A (en) 1997-08-08 1999-09-14 American Standard Inc. Compressor minimum capacity control
JP3431813B2 (ja) * 1997-11-26 2003-07-28 株式会社神戸製鋼所 ２段形スクリュ圧縮機
US6506038B2 (en) 2000-08-15 2003-01-14 Thermo King Corporation Wear-preventing and positioning device for a screw compressor
US6494699B2 (en) 2000-08-15 2002-12-17 Thermo King Corporation Axial unloading lift valve for a compressor and method of making the same
US6467287B2 (en) 2000-08-15 2002-10-22 Thermo King Corporation Valve arrangement for a compressor
JP2006023009A (ja) * 2004-07-08 2006-01-26 Matsushita Electric Ind Co Ltd 空気調和機
JP4110123B2 (ja) * 2004-07-12 2008-07-02 株式会社神戸製鋼所 スクリュ圧縮機
US20060165543A1 (en) * 2005-01-24 2006-07-27 York International Corporation Screw compressor acoustic resonance reduction
AU2006344429A1 (en) * 2006-06-02 2007-12-13 Carrier Corporation Slide valve actuation for overpressure safety
WO2009078178A1 (ja) * 2007-12-17 2009-06-25 Daikin Industries, Ltd. スクリュー圧縮機
GB0821275D0 (en) * 2008-11-20 2008-12-31 Aaf Mcquay Inc Screw compressor
KR200452999Y1 (ko) * 2009-07-02 2011-03-31 에스케이브로드밴드주식회사 통합형 리모트 노드
JP5355336B2 (ja) * 2009-10-05 2013-11-27 荏原冷熱システム株式会社 スクリュー圧縮機および冷凍機
CN101892987A (zh) * 2010-07-06 2010-11-24 阜新金昊空压机有限公司 无级调压式空气压缩机
JP5389755B2 (ja) * 2010-08-30 2014-01-15 日立アプライアンス株式会社 スクリュー圧縮機
EP2616686B1 (en) * 2010-09-14 2017-01-04 Johnson Controls Technology Company Volume ratio control system and method
JP5358608B2 (ja) 2011-03-30 2013-12-04 日立アプライアンス株式会社 スクリュー圧縮機及びこれを用いたチラーユニット
DE102012006363A1 (de) * 2011-04-01 2012-10-04 Rotorcomp Verdichter Gmbh Luftregler für Kompressoren, insbesondere Schraubenkompressoren
JP6006531B2 (ja) * 2012-05-22 2016-10-12 株式会社神戸製鋼所 スクリュ圧縮装置
US9664418B2 (en) * 2013-03-14 2017-05-30 Johnson Controls Technology Company Variable volume screw compressors using proportional valve control
GB2528214C (en) * 2013-05-30 2020-01-29 Mitsubishi Electric Corp Screw compressor and refrigeration cycle apparatus
WO2015051019A1 (en) * 2013-10-01 2015-04-09 Trane International, Inc. Rotary compressors with variable speed and volume control
CN103623879B (zh) * 2013-12-16 2014-11-05 山东大学齐鲁医院 激光定位型移液枪
CN105829724B (zh) * 2013-12-19 2018-10-16 开利公司 包括可变容积指数阀的压缩机
CN106415145B (zh) 2014-04-11 2019-08-06 特灵国际有限公司 Hvac系统和控制
CN104500399B (zh) * 2014-09-15 2016-04-13 汉钟精机股份有限公司 压缩机滑阀位置控制的结构
CN105201789B (zh) * 2015-11-03 2017-05-03 干平 一种变内压比调节装置
JP6742450B2 (ja) * 2016-06-27 2020-08-19 ジョンソン コントロールズ テクノロジー カンパニーＪｏｈｎｓｏｎ Ｃｏｎｔｒｏｌｓ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏｍｐａｎｙ 圧縮機システム、圧縮機を有するチラーの容量制御の方法、及びチラー
BE1025352B1 (nl) * 2017-06-21 2019-02-05 Atlas Copco Airpower Naamloze Vennootschap Inlaatklep voor de inlaat van een compressorelement en compressor en compressorelement daarmee uitgerust
US11118585B2 (en) 2017-10-04 2021-09-14 Ingersoll-Rand Industrial U.S., Inc. Screw compressor with oil injection at multiple volume ratios
US11215182B2 (en) 2018-03-01 2022-01-04 Ingersoll-Rand Industrial U.S., Inc. Multi-stage compressor having interstage lubricant injection via an injection rod
CN109026688B (zh) * 2018-09-30 2024-04-26 厦门华夏国际电力发展有限公司 一种大型工业用空气压缩机压力调节优化冗余系统及方法
WO2020245932A1 (ja) * 2019-06-05 2020-12-10 三菱電機株式会社 スクリュー圧縮機及び冷凍サイクル装置
CN111188769B (zh) * 2020-01-03 2021-05-25 珠海格力电器股份有限公司 螺杆压缩机自动加卸载装置及其控制方法、螺杆压缩机
CN115038873B (zh) * 2020-01-07 2024-10-18 江森自控泰科知识产权控股有限责任合伙公司 用于压缩机的容积比控制系统
EP4088032A1 (en) 2020-01-07 2022-11-16 Johnson Controls Tyco IP Holdings LLP Volume ratio control system for a compressor
CN111255684B (zh) * 2020-03-20 2024-04-09 福建雪人压缩机有限公司 一种半封闭螺杆压缩机
CN114857794B (zh) * 2022-05-26 2023-11-17 青岛海信日立空调系统有限公司 空调机组

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1335024A (en) * 1969-12-31 1973-10-24 Howden Godfrey Ltd Compressor control
US4076461A (en) * 1974-12-09 1978-02-28 Dunham-Bush, Inc. Feedback control system for helical screw rotary compressors
JPS5930919B2 (ja) * 1974-12-24 1984-07-30 北越工業 （株） 液冷式回転圧縮機の液量及び気体容量調整装置
US4342199A (en) * 1980-10-03 1982-08-03 Dunham-Bush, Inc. Screw compressor slide valve engine RPM tracking system
JPS60164693A (ja) * 1984-02-06 1985-08-27 Daikin Ind Ltd スクリユ−圧縮機の容量制御装置
US4583373A (en) * 1984-02-14 1986-04-22 Dunham-Bush, Inc. Constant evaporator pressure slide valve modulator for screw compressor refrigeration system
JPS6193294A (ja) * 1984-10-12 1986-05-12 Daikin Ind Ltd スクリユ−圧縮機の容量制御装置
SE464657B (sv) * 1987-03-04 1991-05-27 Stal Refrigeration Ab Reglersystem foer reglering av en rotationskompressors inre volymfoerhaallande
JPH0315693A (ja) * 1989-06-09 1991-01-24 Ebara Corp スクリュー圧縮装置
US5211026A (en) * 1991-08-19 1993-05-18 American Standard Inc. Combination lift piston/axial port unloader arrangement for a screw compresser

Also Published As

Publication number Publication date
WO1996026368A1 (en) 1996-08-29
KR100350839B1 (ko) 2002-11-18
CA2212942A1 (en) 1996-08-29
EP0811123A1 (en) 1997-12-10
JPH11500511A (ja) 1999-01-12
KR19980702380A (ko) 1998-07-15
DE69515911D1 (de) 2000-04-27
DE69515911T2 (de) 2000-08-03
IN185020B (zh) 2000-10-21
BR9510274A (pt) 1997-11-04
AU4416696A (en) 1996-09-11
CN1080391C (zh) 2002-03-06
US5509273A (en) 1996-04-23
CA2212942C (en) 2001-02-06
CN1176680A (zh) 1998-03-18

Similar Documents

Publication Publication Date Title
EP0811123B1 (en) Gas actuated slide valve in a screw compressor
US5832737A (en) Gas actuated slide valve in a screw compressor
EP0996824B1 (en) Single-source gas actuation for screw compressor slide valve assembly
US4780067A (en) Multicylinder rotary compressor
US4335582A (en) Unloading control system for helical screw compressor refrigeration system
US4052135A (en) Control system for helical screw compressor
US5207568A (en) Rotary screw compressor and method for providing thrust bearing force compensation
US4388048A (en) Stepping type unloading system for helical screw rotary compressor
EP0464315B1 (en) Oil-flooded screw compressor
AU2007279212B2 (en) Screw compressor capacity control
US6739853B1 (en) Compact control mechanism for axial motion control valves in helical screw compressors
US4515540A (en) Variable liquid refrigerant injection port locator for screw compressor equipped with automatic variable volume ratio
US5341658A (en) Fail safe mechanical oil shutoff arrangement for screw compressor
US4553911A (en) Method of coding the oil in screw compressors equipped with automatic variable volume ratio
GB2269424A (en) Preventing oil supply to screw compressor on shutdown
JPS6332948Y2 (zh)
CA1052753A (en) Control system for helical screw compressor
JPH04228892A (ja) 油冷式スクリュ圧縮機
JPH08151987A (ja) スクリュー圧縮機の容量制御装置
JPH0118864Y2 (zh)
JPS61207887A (ja) 自動可変容積比を備えるスクリユ−型コンプレツサ用可変液体冷媒注入ポ−トロケ−タ
KR20070016126A (ko) 압축기 윤활

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19970919

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17Q First examination report despatched

Effective date: 19980331

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 69515911

Country of ref document: DE

Date of ref document: 20000427

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

REG Reference to a national code

Ref country code: GB

Ref legal event code: 732E

REG Reference to a national code

Ref country code: FR

Ref legal event code: TP

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20141121

Year of fee payment: 20

Ref country code: GB

Payment date: 20141126

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20141217

Year of fee payment: 20

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69515911

Country of ref document: DE

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

Expiry date: 20151205

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20151205